Technological Field
The present invention relates to an image forming apparatus such as an MFP (Multi-Functional Peripheral) and a technology related thereto.
Description of the Related Art
There are high-speed startup technologies for making the functions of an MFP usable in a short time such that a user can use them, if the main power of the MFP is turned on (see JP 2013-222394 A and JP 2013-20606 A).
In these high-speed startup technologies, supply of power is not immediately stopped in response to a turn-off operation on a main power switch, and a period (a power supply duration) for continuing supply of power even after the turn-off operation is set, and a process of storing apparatus state information (hereinafter, also referred to as saving object information) in the set period is performed. More specifically, when the main power switch is turned off, a process of storing apparatus state information (such as data stored in a RAM of a controller and data stored in registers of individual processing units) in a non-volatile storage unit (hereinafter, also referred to as a snapshot data acquiring process) is performed for a case where the main power switch is turned on again. Then, if the snapshot data acquiring process finishes, in response to a command from a CPU, supply of power to the image forming apparatus is stopped. Thereafter, if the main power switch is turned on again, a startup process (a high-speed startup process) is performed using the apparatus state information (snapshot data) acquired in the last snapshot data acquiring process. Therefore, the MFP can quickly reach (return to) a startup state (specifically, a state in which it is possible to perform jobs (a ready state)).
In such high-speed startup technologies, when the snapshot data acquiring process or the like is performed in response to a turn-off operation on the main power switch, if a certain situation occurs, for example, the CPU runs out of control, whereby it becomes impossible to transmit a power-off command from the CPU, it may become impossible to stop supply of power to the image forming apparatus.
In contrast with this, JP 2003-15780 A discloses a technology for forcibly turning off the power of an electronic device in a case where a power stop signal is not output from firmware in a predetermined time (a second time (for example, 7 seconds to 15 seconds) after a power stop signal is output by continuously pushing the power switch for a predetermined time (a first time (2 seconds to 5 seconds)).
However, the technology of JP 2003-15780 A just determines whether the predetermined time (the second time (7 seconds to 15 seconds)) has elapsed after the power switch was continuously pushed for the predetermined time (the first time). In other words, it just estimates occurrence of an abnormal state in the CPU only on the basis of the elapsed time from a power-off operation. For this reason, for example, even in a case where the CPU does not actually run out of control and processing of the CPU is just slightly delayed, the power of the electronic device may be forcibly turned off. Like this, the technology of JP 2003-15780 A has room for improvement.